CN115313247A

CN115313247A - Method and apparatus for installing power cables at a deployment site

Info

Publication number: CN115313247A
Application number: CN202210471788.9A
Authority: CN
Inventors: M·巴奇尼; S·曼弗莱迪; M·格诺维斯
Original assignee: Prysmian SpA
Current assignee: Prysmian SpA
Priority date: 2021-05-06
Filing date: 2022-04-29
Publication date: 2022-11-08
Also published as: IT202100011645A1; EP4087074B1; EP4087074A1; EP4087074C0; AU2022203012A1; US20220360057A1; CA3157205A1

Abstract

The present disclosure relates to a method for installing a single power cable span (100) at a deployment site, comprising: -providing a conveyor belt (20) outside the deployment site, having a plurality of positions (28) arranged at predetermined distances from each other along the longitudinal movement direction and moving integrally with the conveyor belt; -repeating the following steps until the single cable span (100) reaches a predetermined position: positioning the first portion (13') of the holder (11) in one of the positions (28); laying a portion of the single cable span (100) on the first portion (13') while advancing the same; connecting the second portion (13 ") with the first portion (13') to lock a portion of the cable span therebetween; when the part of the cable span (100) locked by the holder (11) leaves the conveyor belt (20), the first part (13') of the holder (11) is removed from the position (28) moving together with the conveyor belt (20). The present disclosure also relates to an apparatus for installing a single power cable span (100) at a deployment site.

Description

Method and apparatus for installing power cables at a deployment site

Technical Field

The present disclosure relates to methods and apparatus for installing power cables at a deployment site.

Background

Underground cables are more expensive than equivalent overhead lines because they must be made larger to reduce electrical resistance and heat generation, they require special insulation and/or cable cooling, which is typically provided by forced ventilation or water cooling. This results in higher manufacturing and deployment costs.

However, underground cables help to ensure an uninterrupted power supply, which has hitherto not been common in overhead systems due to e.g. high winds and storms, failure of the supporting structure, etc. Underground cables can transmit power in densely populated areas where land costs are high or where they are environmentally or aesthetically sensitive. Thus, in some areas, the benefits of underground cables outweigh the disadvantages of underground burial.

In the underground installation method of cables, tunnel installation (which is typically about 25-30 m deep) is generally used in cities where direct burial would cause unacceptable damage, or for crossing physical barriers such as rivers, lakes, etc. This has the advantage that other underground services, such as water supply and sewage treatment, are not affected and that there is a greater freedom in selecting the cable path, e.g. to cross a river or a railway.

Installing underground cables in the air (i.e., not buried in the soil), including, for example, installing underground cables in tunnels, can present some difficulties. The cable is provided on a drum. Typically, a single cable span on a drum is shorter than the deployment site (e.g., tunnel), thus requiring multiple splices, thereby increasing cost, installation time, and safety issues. Furthermore, as explained, since high voltage cables used for underground works are heavy (e.g. 400 kv cables weigh about 40 kg/m), deploying a single cable, for example, over a length of 2 km, is problematic in managing the supply drums and the tension exerted on the cable.

Systems have been proposed for installing cables in the air by supporting them on a cart connected to a pull cord or other device so that the cables can be installed in a desired location. However, connecting the cable to the multiple carts required to deploy the cable is a tedious operation and may result in uneven spacing of the carts along the length of the cable.

GB 2383200 relates to cable installation in tunnels. The cable is supplied on drums and motorized rollers are used to guide the cable to the tunnel roof. Within the tunnel, the cables are supported from the support beams by Liang Gunzi, which supports the cable hangers. Liang Gunzi can carry the cable for rolling along the support beam. With the advancing of cable, be provided with Liang Gunzi at the tunnel opening. The cable is fully deployed and supported along its entire length by the support beams.

CN110212458 relates to an apparatus and method for automatically laying cables in tunnels. The device comprises guide rails arranged along the tunnel and is provided with a tractor comprising a traction frame on which the jaws are fixed. Firstly, the cable passes through the guide device and is fixed on the claw; then the position of the claw is adjusted to lead the cable to fall in the concave part, and finally the motor is driven to drive the traction frame to move.

Disclosure of Invention

The applicant aims to provide a method and apparatus for installing power cables at a deployment site (e.g. a tunnel) in which long (e.g. over 2 km) cable spans can be deployed in a simple, fast and accurate manner without the need for splices.

In addition, applicants have aimed to provide a method and apparatus for installing power cables at a deployment site comprising a tunnel, where long (e.g. over 2 km) cable spans can be deployed without the need for personnel within the tunnel and without the use of cumbersome and expensive equipment.

This object is achieved by a method and apparatus in which a plurality of successive holders (e.g. comprising half-grippers) are placed on a conveyor belt at predetermined distances outside the deployment site (e.g. a tunnel) and are engaged successively by a cable span. The holders engaged by the cable spans are connected to a trolley adapted to slide along the rails within the tunnel. Thus, the engagement of the cable span with the holder, and the connection of the holder with the trolley, is quick and simple.

Accordingly, the present disclosure relates to a method of installing a single power cable span at a deployment site, the deployment site comprising a track for supporting the single cable span by a trolley, the method comprising the steps of:

-providing a conveyor belt outside the deployment site, said conveyor belt having a plurality of positions, which are arranged at a predetermined distance from each other along the longitudinal movement direction of the conveyor belt and which move integrally with the conveyor belt;

-repeating the following steps until the single cable span reaches a predetermined position:

o positioning the first portion of the holder in one of said positions when the conveyor belt is moving;

o laying a portion of the single cable span on the first portion of the retainer at the location while advancing the single cable span;

o connecting the second part of the holder with the first part to lock a portion of the cable span therebetween;

o removing the first part of the holder from the position moved with the conveyor belt when the part of the cable span locked by the holder leaves the conveyor belt.

According to one embodiment, the second part of the holder engages with one of the trolleys before being connected with the first part.

According to an alternative embodiment, the second part of the holder engages one of the trolleys after being connected to the first part.

According to another alternative embodiment, the second part of the holder engages with one of the trolleys once the first part is removed from its position.

In one embodiment, the movement of the conveyor belt is caused by the advancement of a single cable span.

In one embodiment, the conveyor belt includes an entry zone, a release zone, and an intermediate zone between the entry zone and the release zone. A single cable span is laid on each first part of the holders of the intermediate zone.

In one embodiment, the first portion of the holder is arranged at the location of the entry zone of the conveyor belt.

In one embodiment the holder means leave said position at the release zone of the conveyor belt.

In one embodiment, the retainers are disposed at locations that are spaced the same distance apart for a given cable deployment.

In one embodiment, the method of the present disclosure further comprises the step of coupling the trolley with a guide rail or track.

According to another aspect, the present disclosure relates to an apparatus for installing a single power cable span at a deployment site, comprising:

-at least one rail fixedly mounted in the deployment site;

-a plurality of trolleys slidably couplable with said at least one rail;

-a plurality of holders for releasably connecting a single cable span to one of the trolleys, each holder comprising a first portion and a second portion;

-a conveyor belt having a plurality of positions arranged at a predetermined distance from each other in the longitudinal direction of movement of the conveyor belt and movable integrally with the conveyor belt, wherein each position is adapted to position the first portion of one of the holders.

In one embodiment, the locations are in the form of bars extending transversely with respect to the direction of translational movement of the conveyor belt.

In one embodiment, the second part of the holder is connected or connectable to one of said trolleys.

In one embodiment, the at least one track comprises a guide rail.

In one embodiment, each of the trolleys includes a cord clamp for releasably connecting the trolley to the draw cord.

Drawings

Further features and advantages will become more apparent from the following description of some embodiments, given by way of example with reference to the accompanying drawings, in which:

fig. 1a-1f show exemplary steps of handling high voltage cables near a tunnel entrance according to one embodiment of the method of the present disclosure.

Fig. 2a-2c and 3a-3e show exemplary steps for installing a single span high voltage cable in a tunnel.

Detailed Description

For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, amounts, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Moreover, all ranges include any combination of the maximum and minimum points disclosed and include any intermediate ranges therein, which ranges may or may not be specifically enumerated herein.

The present disclosure, in at least one of its aspects, can be implemented in accordance with one or more of the following embodiments optionally combined together.

For the purposes of this specification and the appended claims, the words "a" or "an" should be taken to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. This is done merely for convenience and to give general sense to the disclosure.

Referring to the drawings, the object of the method and apparatus according to the present disclosure is to install a single span high voltage cable 100 at a predetermined deployment site. For example, a single span high voltage cable 100 installed from a start point 101 (fig. 1 a) to an end point 102 (fig. 3 e), where a portion of the cable path is inside a tunnel 103 and the rest is outside the tunnel, may be guided from the start point 101 to the tunnel 103 and then pulled to the end point 102, as will be explained below. In the depicted case, the tunnel 103 is located below ground level, and the start 101 and end 102 are located at ground level. The cable path comprises an entrance shaft 104 (fig. 1 f) and an exit shaft 105 (fig. 3 e) communicating with a tunnel entrance 106 and a tunnel exit 107, respectively.

As shown in fig. 1a, the single-wire span 100 may be conveyed at a starting point 101, wherein the single-wire span is wound in a basket or a turntable or drum 109 (e.g., carried by a vehicle 110, such as a wheeled vehicle or even a boat, depending on the location of the starting point 101). The single cable span 100 may be initially detached from the basket 109, for example using a pick-up arm (not shown) to pick up a head portion thereof and move it in a transition structure 111 (fig. 1 b) which guides and keeps the cable 100 moving from the basket 109 towards the entry axis. During the movement of the cable 100 along the transition structure 111, the cable 100 is gradually unloaded from the basket 109.

In the embodiment shown in FIG. 1b, the transition structure 111 may include several different structures, such as a metal frame or channel 112 that generally houses a roller, slide, or pusher 121 for moving, guiding, and/or slowing the advancement of the cable toward the inlet shaft. The transition structure 111 may also include a connection room 113 for connecting the cable span with cables of the network after deployment.

As can be seen from fig. 1c and 1d, a conveyor belt 20 is provided for connecting a single cable span 100 to a device useful for cable deployment. The conveyor belt 20 may be arranged downstream with respect to the transition structure 111 of fig. 1 b. For example, the conveyor belt 20 may be disposed at ground level with respect to the inlet shaft 104 and tunnel inlet 106 (see also fig. 1 f). However, according to another embodiment, the conveyor belt 20 may be positioned at different positions and/or at different levels with respect to the ground.

The conveyor belt 20 forms a closed loop and is supported by a plurality of (optionally idle) rollers 21 which determine the overall shape of the conveyor belt 20. The conveyor belt 20 has an entry zone 22 (where the cable span 100 reaches the conveyor belt 20), a release zone 23 (where the cable span 100 exits the conveyor belt 20), and an intermediate zone 24 between the entry zone 22 and the release zone 23 (where the cable span 100 is supported by the conveyor belt 20). According to the described embodiment, when the rollers 21 are idle, the translational movement of the cable span 100 causes the overall translation of the intermediate zone 24 of the conveyor belt 20, and therefore the rotational movement of the conveyor belt 20 (clockwise, with reference to fig. 1 d). The middle section 24 of the conveyor belt 20 comprises an upper side 25, preferably horizontal, where the cable span 100 is actually connected to the conveyor belt itself.

In one embodiment, the conveyor entry zone 22 may include an upper side 26 that forms an inclined surface that increases in height toward the upper side 25 of the intermediate zone 24.

In one embodiment, the belt release zone 23 may include an upper side 27 that forms a gradually decreasing surface with a decreasing height from the upper side 25 of the intermediate zone 24. The gradually descending surface so formed may be adapted to direct the single cable span 100 downwards (e.g. when the tunnel 103 is in a lower level than the conveyor belt).

The conveyor belt 20 includes a plurality of locations 28 arranged at a predetermined distance from each other along the longitudinal direction of movement of the conveyor belt 20 and moving integrally with the conveyor belt. In one embodiment, the locations 28 are in the form of bars extending substantially perpendicularly with respect to the direction of translational movement of the conveyor belt 20. The location 28 may have any suitable form, from a coloured marking to a marking strip to a block of an alternative shape, to support the first portion 13' of the holder 11 as the conveyor belt advances.

In one embodiment, each holder 11 (and in particular the second portion 13 "thereof) is connected to the trolley 8, as will be described in detail below.

With reference to the embodiment detailed in fig. 1e, each position 28 may comprise a seat 29 at which the first portion 13' of the holder 11 is placed in order to accommodate a cable span portion during movement along the conveyor belt (e.g. during movement along the intermediate zone 24 of the conveyor belt). Once the cable span portion is engaged with the first portion 13', the second portion 13 "of the retainer 11 is connected with the first portion 13' (e.g., by fasteners (not shown)) to releasably lock the portion of the cable span 100 therein. In one embodiment, the second portion 13 "is connected to the trolley 8 on the side opposite to the side where the first portion 13' is connected.

A plurality of holders 11 may be placed at predetermined distances apart at various locations 28 of the conveyor belt 20. The distance between two holders 11 (and correspondingly the distance between the two positions occupied by these holders 11) is generally the same for all holders 11 used for a particular cable deployment. Not all positions 28 are occupied by respective holders 11 during cable deployment. For example, in fig. 1d, two holders 11 carrying respective carts 8 are shown spaced 14 intermediate positions from each other. Corresponding to each position 28 occupied by a holder 11, a portion of the cable span 100 is supported by the respective holder 11.

In one embodiment, the retainer 11 may comprise a first portion 13' and a second portion 13 "that are releasably connectable to lock portions of the cable span 100. For example, the retainer 11 may be a clip, the first portion 13' and the second portion 13 "being two clip halves. In one embodiment, the second portion 13 "may in turn be composed of two sub-components. One of the sub-members may be adapted for connection with the first portion 13' and the other sub-member may be adapted for connection with the trolley 8.

In one embodiment, each holder 11 (in particular the first portion 13' thereof) and the position 28 are configured to: when the portion of the cable span 100 connected to the holder 11 leaves the conveyor belt 20, the holder 11 vacates the position 28 without any further intervention, for example by a user.

Each holder 11 may comprise or be connectable to a respective trolley 8. In one embodiment, the second portion 13 "of the holder 11 may be connected to said trolley 8. As shown in fig. 1d and 1f, the trolley 8 is adapted to slide along a guide rail 30, which may be positioned along or downstream of the conveyor belt 20 (the latter configuration being that of fig. 1c-1 d), for example near the release area 23, for guiding the single-cable span 100 towards the tunnel entrance 106. The guide rail 30 thus supports the trolley 8, which trolley 8 in turn supports the cable span 100 after it has left the conveyor belt 20. In case the conveyor belt 20 and the tunnel 103 are at different levels, the guide rails 30 form a path along the entrance axis 104 for guiding the single cable span from the level of the conveyor belt 20 to the level of the tunnel 103.

It should be noted that the guide track 30 may be rather short or even missing, for example, in case the conveyor belt 20 and the tunnel 103 are at the same level and/or at a short distance.

As can be seen from fig. 1f (where, for clarity only, the guide rail 30 and the track 1 are not depicted), in order to position the head portion 108 of the cable span 100 near the tunnel entrance 106, an auxiliary pulling device (e.g. an auxiliary entrance tractor 115) may be provided at the bottom of the entrance shaft 104, which pulls the cable head portion 108 near the tunnel entrance 106 by means of the entrance auxiliary rope 122. The pusher 121 and the auxiliary inlet tractor 115 may be driven in a synchronized manner.

As can be seen from fig. 2a, at least one rail 1 is mounted in the tunnel 103 and extends in the longitudinal direction of the tunnel from the tunnel entrance 106 to the tunnel exit 107 (fig. 2 c). When a guide rail is provided, the tunnel track 1 may be an extension of the guide rail 30.

In one embodiment, one track 1 is fixed on the tunnel wall for each single cable span 100 to be deployed in the tunnel 103. If there are several cables to be installed, a corresponding number of rails 1 can be installed, which are substantially parallel to each other, before or after the cable span is deployed on the rails (see fig. 2 a). In case the tunnel 103 has a circular or semi-circular cross-section, for example, the rails 1 are mounted circumferentially to the tunnel wall along a cylindrical tunnel wall parallel to the longitudinal axis of the tunnel wall.

In one embodiment, to mount the rails 1 in the tunnel 103, a plurality of rail support structures 2 for supporting the rails 103 are secured to the tunnel walls along the tunnel. The rail support structures 2 are for example made of steel and may be spaced along the length of the tunnel at the same distance, for example no longer than 9 meters. In one embodiment the rail support structure 2 is arc-shaped to fit a circular or semi-circular tunnel wall, as for example shown in fig. 2 a. The track 1 and the track support structure 2 are fixedly mounted in the tunnel 103, as they serve both for laying the single cable span 100 and for maintaining the single cable span in the tunnel 103 after the mounting is completed, as will be described in detail below.

In order to minimize friction with the guide rail 30 and/or the tunnel track 1, the trolley 8 may comprise bearings 9 (fig. 3 a) with a low friction coefficient. In one embodiment the guide rail 30 and/or the tunnel track 1 is I-shaped, with bearings 9 engaging the I-shaped track on both sides.

In one embodiment, the pulling device 3 (e.g. comprising a pulling tractor) is mounted near the tunnel exit 107, e.g. at the exit shaft 105, as shown in fig. 2 c. A rope buffer (e.g. comprising an idler roller 4) is arranged near the tunnel entrance 106, e.g. at the entrance shaft 104, as shown in fig. 2 b. The rope 5 is stored in a rope buffer, for example wound in the idler roller 4, and connected to the rope puller 3 by extending longitudinally along the tunnel 103, so that the rope puller 3 can pull the rope 5 stored in the idler roller 4. In one embodiment, the pull cord 5 is positioned to extend parallel to and adjacent to the track 1.

As shown in fig. 3b, when the first trolley 8 of the part of the cable span 100 connected at the conveyor belt 20 as described above reaches the tunnel track 1 from the guide rail 30 at the tunnel entrance 106, the trolley 8 is then connected to the rope 5. To this end, the trolley 8 comprises a rope clamp 10 for releasably connecting the rope 5 with the trolley 8, as shown in fig. 3 a. In one embodiment, cord gripper 10 includes two halves 12', 12". Once connected with the ropes 5, the trolley 8 carrying the cable span 100 can be made to slide along the rail 1 and the cable 100 can be carried as a whole without applying tensile stress thereto, due to the tensile force exerted by the pulling ropes 5. The pull cord 5 is driven by the pulling device 3 (fig. 2 c).

Then, further trolleys 8, having the same characteristics as the first trolley 8, arrive one after the other at the track 1 at the tunnel entrance 106 and are connected in turn with the ropes 5 as described for the first trolley. Each further trolley 8 is arranged to slide along the rail 1 as described for the first trolley 8. During this operation the single cable span 100 is moved correspondingly further longitudinally along the track 1.

Once the first trolley 8 reaches the end of the tunnel track near the tunnel exit 107, the cable head portion 108 is detached from the first trolley 8.

The single cable span 100 is moved further until the cable head portion 108 is brought to the exit shaft 105 and outside it, in particular, the cable head portion reaches the overhead terminal 102, as shown in fig. 3 e. During this movement, the cable span 100 is detached from the appropriate number of trolleys 8.

In one embodiment, an auxiliary pulling device (e.g., an auxiliary exit tractor 116) is positioned at the overhead terminal 102 (fig. 3 e). The auxiliary pulling device drives an exit auxiliary pull cord (not shown) connected to the cable head portion 108 to pull the single cable span 100 towards the terminus 102. The pulling force exerted by the exit auxiliary pull cord on the cable head portion 108 (and correspondingly on the single cable span 100) is relieved by the pulling force of the pull cord 5 which is still operatively connected to the majority of the length of the single cable span.

An exit transition 117 is provided which guides and holds the single cable span 100 and the exit auxiliary pull cord from the tunnel exit 107 via the exit shaft 105. A second groove 118 may connect terminus 102 and outlet shaft 105.

In one embodiment, a plurality of retainers 120, for example made of steel, are mounted in the outlet shaft 105. The retainer 120 may have rollers for guiding the cable head portion 108 and the auxiliary pull cord.

At the termination 102, the cable head portion 108 of the single-cable span 100 may be connected with one or more power cables of the power grid through a second connection room (not shown).

As described above, in order to lift the head portion 108 of the single cable span 100 out of the tunnel 107, the pulling rope 5 and a predetermined number of trolleys 8 are disconnected from the single cable span 100 and the disconnected trolleys 8 are removed from the track 1 (fig. 3 c). Then, as shown in fig. 3d, the pulling rope 5 (which continues to pull the further trolley 8 and correspondingly the single cable span 100 connected thereto) and the exit auxiliary pulling rope (connected to the cable head portion 118) driven by the auxiliary exit tractor 116 are both pulled (e.g. in a synchronized manner) until the cable head portion 108 reaches a predetermined position outside the tunnel, e.g. until the end point 102 is reached. Depending on the length of the single-cable span 100 to be extracted from the tunnel 103, in addition to the first trolley 8, further trolleys 8 can be disconnected from the pull rope 5 and the single-cable span 100 in succession and removed from the track 1.

In one embodiment, once the cable head portion 108 reaches the terminus 102, at least some or all of the carts 8 within the tunnel 103 may be left in place on the track 1, optionally locked onto the track 1, thereby providing permanent support for the deployed cable span 100. The choice of the number of trolleys 8 to be left in the tunnel 103 may be determined by installation considerations such as cable weight or required sag.

Similarly, once the cable head portion 108 reaches the terminus 102, some of the carriages 8 (if provided) may remain along the guide rail 30. These carriages can be left in place, optionally locked on the guide rails 30.

According to one embodiment, the pull cord is retained within the tunnel in connection with the cart when the cable head portion 108 reaches a predetermined termination point outside the tunnel.

Accordingly, a method of installing a single power cable span 100 in a deployment site comprising a track for supporting a single cable span, such as a tunnel track 1, comprises the steps of:

-providing a conveyor belt 20 as described above;

-repeating the following steps until the cable span 100 reaches a predetermined position (e.g. tunnel entrance 106 or end 102):

o positioning the first portion 13' of the holder 11 to one of the positions 28, for example at the conveyor entry zone 22, when the conveyor 20 is moved. In one embodiment, this step comprises engaging the first portion 13' of the holder 11 in the seat 29 of one of the positions 28, and is repeated for each position spaced a predetermined distance from the position 28 previously occupied. Movement of the conveyor belt 20 may be effected by advancement of a single cable span 100;

o laying a portion of the single cable span in the portion of the holder 11 located to the position 28 and locking the portion of the cable span to the holder 11 while advancing the single cable span 100. These positioning and locking steps may be performed at the belt intermediate section 24. In one embodiment, the locking step may comprise connecting the second portion 13 "with the first portion 13" so as to sandwich the portion of the cable span 100 between the two portions of the holder 11;

o when the portion of the cable span 100 engaged by the retainer 11 leaves the conveyor belt 20 (e.g., at the belt release area 23), the retainer 11 is removed from the location 28 moving with the conveyor belt 20. In one embodiment, this removal step comprises detaching the first portion 13' from the seat 29 of the position 28.

In one embodiment, the holder 11 (e.g., the second portion 13 ") includes or is connected to the cart 8. Alternatively, the method further comprises the step of connecting the holder 11, in particular the second part 13 "already locked to the cable span, to the trolley 8. This step is preferably performed at the intermediate region 24 of the conveyor belt 20.

In one embodiment, after the above-described disengagement, the method further comprises connecting the trolley 8 connected to the cable span section with the guide rail 30 while the single cable span 100 is being advanced. In this way, the single cable span may be directed towards a location (e.g., at a lower level than the conveyor belt), such as towards the tunnel entrance 106.

In the above steps, by pulling the head portion 108 with the auxiliary rope 122, the advance of the single-cable span 100 can be achieved.

Once the cable head portion 108 reaches, for example, the tunnel entrance 106, the method according to the present disclosure may further comprise the following steps, if necessary to move the cable span 100 further, for example, towards another location, for example, the termination 102, until it reaches said location:

at the tunnel entrance 106, the trolley 8 is connected at the tunnel track 1. Since the guide rail 30 and the tunnel track 1 are continuously connected, a single track is formed, this connection being obtained by continuously moving the carriage in a slidable manner from the guide rail 30 to the tunnel track 1;

-connecting the trolley 8 with the pull rope 5;

-moving the trolley 8 along the tunnel track 1 by pulling the pull cord 5;

at the tunnel exit 107, the trolley 8 is disconnected from the pull rope 5 and the single cable span 100 and removed from the tunnel track 1.

In one embodiment, the method further comprises the steps of: when the cable head portion 108 reaches the desired end position, at least the carriage 8 closest to the tunnel exit 107 is locked on the tunnel track 1.

Installation is considered complete when the cable head portion reaches a predetermined termination point outside the tunnel. The single cable span thus installed may then be connected to the power network via, for example, the first and second connection rooms described above.

Claims

1. A method for installing a single power cable span (100) at a deployment site, the deployment site comprising a track (1:

-providing a conveyor belt (20) outside the deployment site, said conveyor belt (20) having a plurality of locations (28) arranged at a predetermined distance from each other along the longitudinal movement direction of the conveyor belt (20) and moving integrally with the conveyor belt;

-repeating the following steps until the single power cable span (100) reaches a predetermined position:

o positioning the first portion (13') of the holder (11) in one of said plurality of positions (28) while the conveyor belt (20) is moving;

o laying a portion of a single power cable span (100) on said first portion (13') of the holder (11) at a location (28) moving with the conveyor belt (20) while advancing it;

o connecting the second portion (13 ") of the retainer (11) with the first portion (13') to lock the portion of the single power cable span therebetween;

o removing the first part (13') of the holder (11) from the position (28) moving with the conveyor belt (20) when the part of the single power cable span (100) locked by the holder (11) leaves the conveyor belt (20).

2. Method according to claim 1, wherein the second part (13 ") of the holder (11) is engaged with one trolley (8) before being connected with the first part (13').

3. Method according to claim 1, wherein the second part (13 ") of the holder (11) is engaged with one trolley (8) after connection with the first part (13').

4. A method as claimed in claim 1, wherein the second portion (13 ") of the holder (11) is engaged with one trolley (8) once the first portion (13') is removed from its position (28).

5. The method according to claim 1, wherein the movement of the conveyor belt (20) is caused by the advancement of a single power cable span (100).

6. A method according to claim 1, wherein the conveyor belt (20) comprises an entrance zone (22), a release zone (23) and an intermediate zone (24) between the entrance zone (22) and the release zone (23), wherein the single power cable span (100) is laid over the first portion (13') at the intermediate zone (24).

7. Method according to claim 6, wherein the first portion (13') of the holder (11) is positioned at one of the plurality of locations (28) in the entrance zone (22) of the conveyor belt (20).

8. Method according to claim 6, wherein the holder (11) leaves the position (28) at the release zone (23) of the conveyor belt.

9. The method according to claim 1, wherein for a given cable deployment, the holders (11) are provided at locations (28) that are spaced apart by the same distance.

10. Method according to claim 1, further comprising the step of connecting the trolley (8) with the guide rail (30) or the track (1).

11. An apparatus for installing a single power cable span (100) at a deployment site, comprising:

-at least one rail (1;

-a plurality of trolleys (8) slidably coupled with said at least one rail (1;

-a plurality of holders (11) for releasably connecting a single power cable span (100) to one of the trolleys (8), each holder comprising a first portion (13') and a second portion (13 ");

-a conveyor belt (20) having a plurality of locations (28) arranged at a predetermined distance from each other in a longitudinal direction of movement of the conveyor belt (20) and movable integrally with the conveyor belt, wherein each location (28) is adapted to position a first portion (13') of one of the plurality of holders (11).

12. Apparatus according to claim 11, wherein said plurality of locations (28) is in the form of bars extending transversely with respect to the direction of translational movement of the conveyor belt.

13. Apparatus according to claim 11, wherein the second portion (13 ") of the holder (11) is connected or connectable to one of said plurality of trolleys (8).

14. The apparatus of claim 11, wherein the at least one track comprises a guide rail (30).

15. An apparatus according to claim 11, wherein each trolley (8) comprises a rope clamp (10) for releasably connecting the trolley (8) with the pull rope (5).